mp3 editing directly


I’m working with mp3 loops and need to edit them. However, when I open an mp3 make the neccessary edits to the beginning and ending of a file for it to loop correctly and then save it, the resulting mp3 has extra space at the top and tail.

This leads me to believe that wavelab 7 is converting an mp3 into pcm audio, allowing me to edit it and then re-encoding it back to mp3 which then adds the extra mp3 frames to the top and tail that I just removed.

Is there anyway to edit an mp3 and save it directly with Wavelab 7 without having Wavelab convert the files but keeping them as mp3’s throughout the process?

This is a pretty common dilemma nowadays for editing audio for flash or ios/android apps.

WaveLab does the convertion, as you say.
But my principle, mp3 is based on frames containing many samples, hence it is not possible to make sample accurate loops. Direct editing would not change this.

Mp33 is a distribution format, and not an edit format.

PG thanks for the response.
You are correct that MP3 is a distribution format and based on frames of typically 1152 samples.

However, there are a few sites that explain step by step how to edit the frames of an MP3 so that you can make MP3’s that will loop cleanly and without gaps. Unfortunately, they require that you edit the mp3 after it is made and all the utilities I’ve seen mentinoed to do that are PC only. Since I use Wavelab 7 on Mac OSX, I thought I’d start by asking here.

The situation is that for Flash and some other common video game formats, clients are requesting MP3’s that loop and while it isn’t ideal, its certainly a client demand that I’m getting far more often so It might be something to consider adding to Wavelab.


maybe this tools will do it ?

regards S-EH

Another possibility is the Freeware mp3DirectCut (for Windows or Linux). I use that to fastly trim podcasts for private use - very quick, but it also has looping options.

Luck, Arjan

I thought that all mp3’s needed to have a footer and header area for data, such as text and graphics.

I tried the MP3 trimer but couldn’t edit precisely at teh sample level only milliseconds.

I’ll try Fission next…

Thanks for the tips…

The mp3 file is shorter precisely because it doesn’t contain information at a sample level, so there is no way around this limitation without decoding and reencoding (which brings its own issues, of course).